What range is listed as a typical pre-bottling free SO2 level for white, red, and sweet wines?

• A. 25-45 mg/L
• B. 30-55 mg/L
• C. 30-60 mg/L
• D. 20-40 mg/L

Answer: (B)

Free SO2 is the protective form of sulfur dioxide in wine, acting as an antioxidant and antimicrobial agent. The pre-bottling target is set to provide enough unbound SO2 across typical pH levels and styles, so a range of about 30–55 mg/L covers white, red, and sweet wines effectively. Reds often have higher pH, so they benefit from the upper end of this range to ensure sufficient molecular SO2, while whites, with lower pH, can be adequately protected toward the lower end. Sweet wines also fit within this spread, balancing protection with sensory considerations. Other ranges either undershoot protection for red and sweet styles or extend beyond common practice, making 30–55 mg/L the best overall fit.